Three twists to get to grips with at National? (7)
I believe the answer is:
theatre
'national?' is the definition.
(the National Theatre or NT is an example)
'three twists to get to grips with at' is the wordplay.
'twists' is an anagram indicator (I've seen 'twist' mean this).
'to get to grips with' indicates putting letters inside.
'three' anagrammed gives 'there'.
'there' going around 'at' is 'THEATRE'.
(Other definitions for theatre that I've seen before include "(Lecture) room" , "within which one may operate" , "(Military) field of action" , "Space for dramatic art and surgery" , "eg The Globe" .)